I'm a new HBD owner, but I've played WIS games quite a bit in the past so I feel like I have a good handle on the conceptual aspects of the game. I'm pleased with the preformance of the ML team I've assembled so far too. What I'm struggling with is the progression aspect of the game. I have a few solid to good prospects in my system, and I'm concerned that I may be hampering their growth because I don't understand the code involved here.

First, what are the "bumps" i keep reading about? Opening day bump, promotion bump, injury bump? Never seen this in other games and didn't find much explaining it in what I've read? Also, are the corresponding penalties?

Second, am I free to move players from one level to the next and back in the Minors without fear of derailing their development? I have a few guys I'd like to bump down a level due to over anxious decisions when I first took over, but do not want to suffer from a penalty?

Lastly, anyone who would like to share their system/secret/tips on promotions, timing of promotions and development in general would be greatly greatly appreciated.

The "bumps" are periodic updates to the player's ratings throughout the season. You get one at the end of spring training "Opening Day", a handful (four or five) during the season "Regular Season", and you could also get one via a promotion "Promotion". If a player is injured and spends time on the disabled list, you'll also see a bump when they are eligible be to activated "Injury Recovery". For younger players, the bumps are usually ratings improving. For veterans in their prime, the bumps have have no change, and for older players, the bumps may actually be a decline of ratings.

You'll also see ratings hits for certain events, such as injuries ("Time of Injury") or for demotions ("Demotion"). In general, you want to be very careful about demoting players downward becasue you run the risk of demotion hits. If it's a "roster filler" type player, i.e. one with no chance of making it to the major leagues, there's no reason to be overly concerned about them seeing demotion penalties.

The keys to maximizing development are coaching(learned skills), training(physical skills) and playing time.

Play your true prospects as much as possible while watching fatigue. Once they reach a fatigue level that makes you uncomfortable, deactivate them for a few days. Much debate can be made of what's an "acceptable" coach. I'm comfortable with 50s in LoA/HiA and 60s in AA/AAA. Others are not. If you fail in coach hiring, do not leave a prospect with what you consider a bad coach. Promote them. Finally, 20m in training works for me. That's the most you can budget and it will help players max out in stamina, power, etc, etc. Some are comfortable with less than 20m.

Don't forget to invite your top prospects to spring training and give them adequate play time during it. Spring training exposes prospects to ML coaching and the higher coaching ratings should help progress their development at least for that one development cycle per season.